House dust mites are known as major causes of allergic diseases such as atopic dermatitis and bronchial asthma. Conventionally, desensitization therapy that uses causative substances of allergies as therapeutic agents for allergic diseases is regarded as the most important basic remedy. In particular, the desensitization therapy is broadly conducted for diseases such as pollinosis, house dust allergies, and fungal allergies, which are induced by antigens such as inhalant allergens that are difficult to avoid. However, the desensitization therapy involves the risk of anaphylaxis due to the action of sensitizing antigens, so that administration of safe therapeutic antigens is required. Such safe sensitizing antigens are under research.
Regarding mite allergic diseases, 2 types of mites, Dermatophagoides pteronyssinus and Dermatophagoides farinae, have been reported as allergen sources in house dust (see Non-patent documents 1 and 2). Major mite allergens have been fractionated from these mites. These mite allergens are known to be a glycoprotein (pI 4.6 to 7.2) with a molecular weight between 24 kD and 28 kD and/or a protein (pI 5 to 7.2) with a molecular weight between 14.5 kD and 20 kD contained in mite excretion and/or mite bodies (see Non-patent documents 3 to 7).
Regarding the mite allergen genes, Der p 1 (molecular weight: 25,371) and Der p 2 (molecular weight: 14,131) which are major allergens of Dermatophagoides pteronyssinus and Der f 1 (molecular weight: 25,191) and Der f 2 (molecular weight: 14,021) which are major allergens of Dermatophagoides farinae have been cloned and the nucleotide sequences thereof have also been determined (see Non-patent documents 8 to 15). Recombinant allergens based on these allergens have also been prepared, and research concerning the same has proceeded. Moreover, the nucleotide sequence of Der f 3, an allergen with a molecular weight of approximately 30,000, has also been reported (see Non-patent document 16). Furthermore, as mite allergens, ma 10, ma 3, ma 15, ma 29, ma 44, ma 50, ma 113, ma 114, and ma 115 (see Patent document 1) have also been reported. Moreover, ma 124, which exerts strong crossreactivity with an anti-Der f 2 serum, has also been reported (see Patent document 2).
Furthermore, it has been reported concerning dogs that 98-kDa Der f 15, 109-kDa Der f 15 (see Non-patent document 17), and 60-kDa Der f 18 (see Non-patent document 18) are allergens with which IgE strongly reacts.
As a method for diagnosing mite allergic diseases, an intradermal reaction test has conventionally been used as a mainstream method, which is based on a patient's history and uses house dust extracts and/or mite body extracts. This method (test) has been used in combination with a RAST (radio allergosorbent test) method that involves serum IgE antibody titer (relative value) measurement, an inhalation induction test, a nasal mucous membrane provocation test, and the like. However, it has remained considerably difficult to directly diagnose mite allergic diseases.
A desensitization therapeutic method for bronchial asthma has been conventionally performed, which uses a house dust extract and a house dust mite as a specific allergen. However, the composition of house dust has not been analyzed sufficiently. Moreover, house dust contains many types of impurities that can induce anaphylaxis. Hence, the doses of house dust in such cases are extremely limited. Accordingly, conventional desensitization treatment can have effects at extremely low levels. Therefore, more effective and safer antigens for desensitization treatment have been desired. It has been conventionally known that allergens effective for desensitization treatment are present in fractions of high-molecular-weight crude mite excretions. From such fractions, it has been impossible to obtain mite allergens in amounts sufficient for desensitization treatment. Therefore, with methods that involve extraction and purification of mite allergens from products obtained by raising mites, achieving a stable supply of antigens for treatment is difficult. Furthermore, as described above, various recombinant mite allergens have been conventionally reported with the use of gene recombination techniques. However, it cannot be said that these allergens are always effective for actual treatment. Provision of a recombinant mite allergen with more effective, new, and greater mite allergen activity has been desired.    Patent document 1 JP Patent Publication (Kokai) No. 7-112999 A (1995)    Patent document 2 JP Patent Publication (Kokai) No. 7-278190 A (1995)    Non-patent document 1 Allerg. Asthma, 10, 329-334 (1964)    Non-patent document 2 J. Allergy, 42, 14-28 (1968)    Non-patent document 3 J. Immunol., 125, 587-592 (1980)    Non-patent document 4 J. Allergy Clin. Immunol., 76, 753-761 (1985)    Non-patent document 5 Immunol., 46, 679-687 (1982)    Non-patent document 6 Int. Arch. Allergy Appl. Immunol., 81, 214-223 (1986)    Non-patent document 7 J. Allergy Clin. Immunol., 75, 686-692 (1985)    Non-patent document 8 Int. Arch. Allergy Appl. Immunol., 85, 127-129 (1988)    Non-patent document 9 J. Exp. Med., 167, 175-182 (1988)    Non-patent document 10 J. Exp. Med., 170, 1457-1462 (1989)    Non-patent document 11 Int. Arch. Allergy Appl. Immunol., 91, 118-123 (1990)    Non-patent document 12 Int. Arch. Allergy Appl. Immunol., 91, 124-129 (1990)    Non-patent document 13 Jpn. J. Allergol., 39, 557-561 (1990)    Non-patent document 14 Clinical and Experimental Allergy, 21, 25-32 (1991)    Non-patent document 15 Clinical and Experimental Allergy, 21, 33-37 (1991)    Non-patent document 16 FEBS Lett., 377, 62-66 (1995)    Non-patent document 17 Vet. Immunol. Immunopathol, 78, 231-247 (2001)    Non-patent document 18 J. Allergy Clin. Immunol, 112, 79-86 (2003)